Q: Can you describe the first test of a thermonuclear device. What sort of
contraption was "Mike"? And when it works what does it prove?

RR: The first hydrogen device that we detonated was something only the United
States would have built. It had 300 or 400 kilograms of liquid deuterium in a
big tank in the middle, a cryogenic tank, so therefore layers and layers and
layers of various insulating materials and reflective materials. That was the
heart of it. And it had to be kept cooled down to minus-whatever, close to
absolute zero. This required immense ingenuity, and no one had ever worked
with such large quantities of liquid hydrogen before.

What they ended up with was this big tank, the size of a small railroad tank
car, with a tank of liquid deuterium in the middle, and surrounding that, the
largest natural uranium casting ever made, which would serve as a tamper to
hold things together, and also would fission. Most of the yield from the
hydrogen bomb comes from fissioning ordinary uranium, which normally doesn't
fission...To keep the cold in, to keep the heat out, the inside of this giant
uranium casting had to be covered with a surface of gold foil. And as one of
the engineers told me: We got a little sign painter from Albuquerque to come
up, and got him security clearance, and he sat there with these little leaves
of gold foil, which come in little books (25 leaves to the book), gold foiling
the entire interior of this huge device so that it glowed like a mirror when
they were through.

It was such a big machine to build, they made the decision that the blueprints
would be full size. And that meant that they had to make blueprints 40 feet
long. So they took an old building off at one side of the laboratory, and
built a balcony in the building so you could get high enough to look down on
the blueprints and actually get a sense of what you were doing. And you could
crawl around on the blueprints and say, "What's that?" "Oh, don't you
remember? We said we'd put that device there." "Oh yeah, that's right." It
was this immense and very exuberant engineering project.

When they finally then took it all to Eniwetok (to give just one little
glimpse of all the complexities of it), they used ordinary liquid hydrogen to
keep the deuterium cooled. And they had a lot left over, so they had to burn
it off. How else would you get rid of it? So they vented it out into the air.
Liquid hydrogen, when it burns, burns with no visible flame at all, just a sort
of turbulence in the air. Birds would fly by, not knowing that this was here,
and would be crisped instantly: a little miniature version of what would happen
to all the bird population of that part of the Pacific when this huge explosion
finally went off.

It was a big project. And they had managed to complete it in a very short
period of time, little more than a year.

Q: When "Mike" went off it totally vaporized the island of Elugelab, didn't
it?

RR: The fireball melted a crater, completely eliminated this little island from
the Pacific. It melted a crater several hundred yards deep and a mile or more
in diameter. So that to this day, if you fly over that part of the Pacific,
there's suddenly this deep blue, perfectly circular hole there. It was such a
huge explosion that it frightened people who were familiar with fission
explosions. They were on ships 20-30 miles away. Several of them told me the
same thing: It felt as if it would never stop expanding. And indeed, the
cloud reached an altitude of more than 100,000 feet, and a diameter of 27
miles. It was a terrifying experience. But it worked.